• Title/Summary/Keyword: False-negative results

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Influence of Fatigability on the Timing of Reassessment in the Treatment of Posterior Canal Benign Paroxysmal Positional Vertigo (후반고리관 양성돌발두위현훈의 치료에서 재평가 시기에 대한 피로 현상의 영향)

  • Kim, Chang-Hee;Shin, Jung Eun;Shin, Yong Gook;Song, Mee Hyun;Shim, Dae Bo
    • Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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    • v.61 no.12
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    • pp.658-662
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    • 2018
  • Background and Objectives The early assessment of treatment is not done for benign paroxysmal positional vertigo (BPPV) since the well-known phenomenon of fatigability after a repeated positional test can mimic successful treatment. The aim of this study is to evaluate the clinical implication of 'fatigability' after Epley maneuver and to identify the therapeutic efficacy of Epley maneuver in posterior canal BPPV (PC-BPPV). Subjects and Method This study was prospectively conducted by two dizziness clinics on 51 consecutive patients diagnosed with PC-BPPV. All patients included in the study received Epley maneuver treatment. The therapeutic results were reassessed immediately after a single trial of Epley maneuver. After 30 minutes, results were reassessed repeatedly to confirm the fatigability of diagnostic procedure immediately after treatment. If the treatment was not successful after 30 minutes, Epley maneuver was repeatedly performed until complete resolution. Results Immediately after the first maneuver, 45 of 51 (88.2%) patients had neither vertigo nor nystagmus during the positional test. All patients demonstrated complete resolution after receiving one to three Epley maneuvers on the day of diagnosis. 'Fatigability (false negative result)' was confirmed for only one case (1 of 6 patients, 16.7%), in which nystagmus was observed after 30 minutes but not identified immediately after the first Epley maneuver. Conclusion The therapeutic efficacy of Epley maneuver is very high in PC-BPPV. Considering the possibility of fatigability when reassessment is performed immediately after therapeutic maneuver, clinicians should avoid assessing the outcome immediately after treatment in patients with PC-BPPV.

The Role of Camera-Based Coincidence Positron Emission Tomography in Nodal Staging of Non-Small Cell Lung Cancer (비소세포폐암의 림프절 병기 결정에서 Coincidence PET의 역할)

  • Lee, Sun-Min;Choi, Young-Hwa;Oh, Yoon-Jung;Cheong, Seong-Cheoll;Park, Kwang-Joo;Hwang, Sung-Chul;Lee, Yi-Hyeong;Park, Chan-H;Hahn, Myung-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.47 no.5
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    • pp.642-649
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    • 1999
  • Background: It is very important to determine an accurate staging of the non-small cell lung cancer(NSCLC) for an assessment of operability and it's prognosis. However, it is difficult to evaluate tumor involvement of mediastinal lymph nodes accurately utilizing noninvasive imaging modalities. PET is one of the sensitive and specific imaging modality. Unfortunately PET is limited use because of prohibitive cost involved with it's operation. Recently hybrid SPECT/PET(single photon emission computed tomography/positron emission tomography) camera based PET imaging was introduced with relatively low cost. We evaluated the usefulness of coincidence detection(CoDe) PET in the detection of metastasis to the mediastinal lymph nodes in patients with NSCLC. Methods: Twenty one patients with NSCLC were evaluated by CT or MRI and they were considered operable. CoDe PET was performed in all 21 patients prior to surgery. Tomographic slices of axial, coronal and sagittal planes were visually analysed. At surgery, mediastinal lymph nodes were removed and histological diagnosis was performed. CoDe PET findings were correlated with histological findings. Results: Twenty of 21 primary tumor masses were detected by the CoDe PET. Thirteen of 21 patients was correctly diagnosed mediastinal lymph node metastasis by the CoDe PET. Pathological N0 was 14 cases and the specificity of N0 of CoDe PET was 64.3%. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of N1 node was 83.3%, 73.3%, 55.6%, 91.7%, and 76.2% respectively. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of N2 node was 60.0%, 87.5%, 60.0%,87.5%, and 90.0% respectively. There were 3 false negative cases but the size of the 3 nodes were less than 1cm. The size of true positive nodes were 1.1cm, 1.0cm, 0.5cm respectively. There were 1 false positive among the 12 lymph nodes which were larger than 1cm. False positive cases consisted of 1 tuberculosis case, 1 pneumoconiosis case and 1 anthracosis case. Conclusion: CoDe PET has relatively high negative predictive value in the enlarged lymph node in staging of mediastinal nodes in patients with NSCLC. Therefore CoDe PET is useful in ruling out metastasis of enlarged N3 nodes. However, further study is needed including more number of patients in the future.

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Rapid prenatal diagnosis of chromosome aneuploidies in 943 uncultured amniotic fluid samples by fluorescence in situ hybridization (FISH)

  • Han, Sung-Hee;Kang, Jeom-Soon;An, Jeong-Wook;Lee, An-Na;Yang, Young-Ho;Lee, Kyu-Pum;Lee, Kyoung-Ryul
    • Journal of Genetic Medicine
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    • v.5 no.1
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    • pp.47-54
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    • 2008
  • Purpose : Fluorescence in situ hybridization (FISH) on uncultured amniotic fluid cells offers the opportunity for rapid screening of aneuploidies and has become an integral part of the current practice in many clinical cytogenetics laboratories. Here, we retrospectively analyzed the results of interphase FISH in 943 amniotic fluid samples and assessed the efficiency of FISH for rapid detection of aneuploidies. Methods : Interphase FISH for chromosome 13, 18, and 21 was performed in 943 consecutive amniotic fluid samples for rapid diagnosis of aneuploidies referred from 2004 to 2006. Karyotypes from standard cytogenetic analysis were compared to the FISH results. Results : A total of 45 chromosomal rearrangements (4.8%) were found after conventional cytogenetic analysis of the 943 amniotic fluid. After exclusion of known familiar chromosomal rearrangements and inversions (2.1%, 20/943), 2.7% (25/943) were found to have chromosomal abnormalities. Of this group, 0.7% (6/943) were chromosomal abnormalities not detectable by FISH and 2.0% (19/943) were numerical abnormalities detectable by FISH. All 14 cases of Down syndrome (Classic type, 13 cases; Robertsonian type, 1 case) and 5 cases of trisomy 18 were diagnosed and detected by FISH and there were no false-positive or -negative results (specificity and sensitivity=100%). Conclusion : The present study demonstrates that FISH can provide a rapid and sensitive clinical method for prenatal identification of chromosome aneuploidies. However, careful genetic counseling is essential to explain the limitations of FISH, including the inability to detect all chromosomal abnormalities and the possibilities of uninformative or false-negative results in some cases.

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Evaluation for detection of Cryptosporidium oocysts in diarrheal feces of calves (야외 송아지 설사변에서 작은와포자충 검출에 대한 평가)

  • Wi, Seong-Hwan;Ju, Hu-Don;Gang, Yeong-Bae
    • Parasites, Hosts and Diseases
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    • v.34 no.2
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    • pp.121-126
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    • 1996
  • For the detection of Cwptospori,mum oocysts, fecal samples were collected from 201 calves which showed diarrhea. Among the 201 samples, 29 samples (14.4%) were positive for Cwptosporinium spry. by the DMSO-modified acid-fast stain (MAFS) , 23 samples (11.4%) were positive by commercial kit (Meridian Diagnostics, Cincinnati, Ohiol and 23 by the indirect immunofluorescence antibody (IFA )assay employing the monoclonal antibody (mAb C6). When tested by both IFA and MAFS, 20 fecal samples were positive for Cwptosporinium oocysts whereas 169 fecal samples were negative. If the MAFS is considered a standard method for oocyst detection, the IFA showed 69% of sensitivity and 98% of specificity. When tested by both IFA and commercial kit, 22 fecal samples were positive for Cwptospori,mum oocysts while 177 samples were negative. One sample tested by IFA was found to be false negative, when compared with the results by commercial kit. The sensitivity of IFA was calculated as high as 96%; the specificity as 99% and the predictive value was also 99%. In the present study, IFA employing the nAb C6 revealed that 23 samples (11.4%) were positive among the 201 calves showing diarrhea. Of 23 IFA positive samples, 4 samples (5%) showed cryptosporidial oocysts more than 105 OPG Therefore. it is concluded that the calves showing cryptosporidial oocysts more than 105 OPG in the feces were highly associated with clinical cryptosporidiosis.

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Monitoring of Commercial Red Pepper Powders for Their Irradiation Status (물리적 확인시험법을 이용한 시판 유통 중인 고춧가루의 방사선 조사여부 판별 모니터링)

  • Jeong, Mi-Seon;Ahn, Jae-Jun;Akram, Kashif;Kim, Gui-Ran;Kim, Hyun-Ku;Kwon, Joong-Ho
    • Korean Journal of Food Science and Technology
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    • v.44 no.6
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    • pp.673-679
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    • 2012
  • Ten commercially available red pepper powders were investigated using photostimulated-luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR) analyses to confirm their irradiation status. The application of PSL, TL, and ESR analyses was also confirmed by in-house irradiation. In PSL-based screening, all samples gave negative photon counts (<700 PCs). The PSL calibration dose (1 kGy) showed a low sensitivity of 4 samples, while the others provided reliable screening results. TL glow curves demonstrated maximum peaks after $250^{\circ}C$ for the 6 samples; however 4 samples gave complex TL glow curves with maximum peaks in the range of $185-260^{\circ}C$ (radiation-specific), which could be the effect of an irradiated component in low concentration as the TL ratios of all samples were <0.1. Radiation-specific ESR features were absent in the all commercial samples. Variable irradiation detection properties were found; where the TL analysis showed the possible presence of an irradiated component in 4 samples requiring further monitoring and investigation.

Evaluation of Clinical Utility and Biologic False Positive (BFP) Rates in Automated Syphilis Test Kits for Syphilis Screening (자동화 매독검사 키트의 임상적 유용성 및 생물학적 위양성률의 평가)

  • Kim, Sung-Man;Lee, Jehoon
    • Korean Journal of Clinical Laboratory Science
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    • v.41 no.1
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    • pp.42-46
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    • 2009
  • Unlike most bacteria, Treponema pallidum subspecies cannot be readily isolated or sustained in cell culture for numerous generations. In korea, two non treponemal tests are currently considered as standard; the VDRL slide test and RPR card test. These tests are based on an antigen composed of an alcoholic solution containing measured amount of cardiolipin, cholesterol, and sufficient purified lecithin to produce reactivity. The nontreponemal reagin tests measure immunoglobulin M (IgM) and IgG to lipoidal material released from damaged host cells as well as to lipoprotein-like material and possibly by cardiolipin released from the treponemes. The object of the evaluation was to evaluate the performance of the Mediace RPR kit on the automated biochemistry analyzer system as a method for screen method of syphilis as well as to identify BFP possibility. For evaluation of routine screening test, a total 2,380 specimens tested by Mediace RPR from 28th Oct, 2007 to 22th Feb, 2008. For evaluation of BFP possiblility, we measured samples which have potential BFP reaction in Syphilis test such as ANA (anti-nuclear antibody) positive (135 samples), CRP (C-reactive protein) positive (100 samples), RF (Rheumatoid factor) positive (26 samples), and other potential BFP cases (17 samples) including total 278 samples. These samples were tested quantitative test Mediace RPR with Hitachi 7600 P module. For comparison with current manual test, VDRL slide test were performed. Of these 2380 specimens, 2350 were negative, 30 were positive, and one were positive with TPHA. Both methods agreed for 2356 (98.9%) samples. Of the 30 samples showed positive results over 1.0 R.U, 6 samples showed positive results with VDRL test. Of these 6 samples, 1 samples showed positive with TPHA test. The combination of the Automated Biochemistry analyzer and VDRL test for retest can be increase efficiency of syphilis screening test.

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TORCH (toxoplasmosis, rubella, cytomegalovirus, and herpes simplex virus) screening of small for gestational age and intrauterine growth restricted neonates: efficacy study in a single institute in Korea

  • Chung, Mi Hae;Shin, Chan Ok;Lee, Juyoung
    • Clinical and Experimental Pediatrics
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    • v.61 no.4
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    • pp.114-120
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    • 2018
  • Purpose: Routine screening for toxoplasmosis, rubella, cytomegalovirus (CMV), and herpes simplex virus (TORCH) in intrauterine growth restriction (IUGR) and small for gestational age (SGA) neonates has become a common practice. However, the incidence of TORCH varies across countries, and the cost of TORCH testing may be disadvantageous compared to disease-specific screening. To evaluate the efficacy of TORCH screening, the medical charts of IUGR or SGA neonates born in a single institution in Bucheon, Korea from 2011 to 2015 were reviewed. Methods: The clinical data of the 126 IUGR or SGA neonates were gathered, including gestational age, Apgar scores, neonatal sonographic findings, chromosome study, morbidities, developmental follow-up, and growth catch-up. Maternal factors including underlying maternal disease and fetal sonography were collected, and placental findings were recorded when available. TORCH screening was done using serum IgM, CMV urine culture, quantification of CMV DNA with real-time polymerase chain reaction, and rapid plasma reagin qualitative test for syphilis. Tests were repeated only for those with positive results. Results: Of the 119 TORCH screenings, only one was positive for toxoplasmosis IgM. This result was deemed false positive due to negative IgM on repeated testing and the absence of clinical symptoms. Conclusion: Considering the incidence and risk of TORCH in Korea, the financial burden of TORCH screening, and the single positive TORCH finding in our study, we suggest disease-specific screening based on maternal history and the clinical symptoms of the neonate. Regarding CMV, which may present asymptomatically, universal screening may be appropriate upon cost-benefit analysis.

Radiographic Uterine Diameter Evaluation for the Detection of Uterine Disease in Dogs: A Retrospective Study

  • Yun, Sookyung;Lee, Jeosoon;Choi, Mincheol;Yoon, Junghee
    • Journal of Veterinary Clinics
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    • v.34 no.6
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    • pp.420-424
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    • 2017
  • Cystic endometrial hyperplasia (CEH) and uterine dilation (hydro-, muco-, hemato- and pyometra) are common uterine diseases in intact female dogs. The aim of the present study was to assess the usefulness of digital abdominal radiography in diagnosing uterine disease in intact female dogs. Two hundred and thirteen intact female dogs were included, and were classified into four groups on the basis of radiographic uterine visibility (visible/invisible) and ultrasonographic findings (normal uterus/abnormal uterine condition including CEH and uterine dilation). For each dog, the ratio of the maximum uterine diameter to the height of the fifth lumbar vertebral body (U/L5 ratio) was calculated on radiographs. There were 78 and 135 dogs in the normal and abnormal groups, respectively; 34.6% normal and 53.5% abnormal uteri were visible on abdominal radiographs. Our results suggested that a mean U/L5 ratio of $1.18{\pm}0.53$ ($mean{\pm}2SD$) indicated a normal radiographic uterus diameter, and that a value of > 1.60 should be used as an indicator of uterine disease in clinical practice. However, because false negative results were noted, radiography cannot replace ultrasonography for assessment of the uterus.

QSAR Approach for Toxicity Prediction of Chemicals Used in Electronics Industries (전자산업에서 사용하는 화학물질의 독성예측을 위한 QSAR 접근법)

  • Kim, Jiyoung;Choi, Kwangmin;Kim, Kwansick;Kim, Dongil
    • Journal of Environmental Health Sciences
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    • v.40 no.2
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    • pp.105-113
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    • 2014
  • Objectives: It is necessary to apply quantitative structure activity relationship (QSAR) for the various chemicals with insufficient toxicity data that are used in the workplace, based on the precautionary principle. This study aims to find application plan of QSAR software tool for predicting health hazards such as genetic toxicity, and carcinogenicity for some chemicals used in the electronics industries. Methods: Toxicity prediction of 21 chemicals such as 5-aminotetrazole, ethyl lactate, digallium trioxide, etc. used in electronics industries was assessed by Toxicity Prediction by Komputer Assisted Technology (TOPKAT). In order to identify the suitability and reliability of carcinogenicity prediction, 25 chemicals such as 4-aminobiphenyl, ethylene oxide, etc. which are classified as Group 1 carcinogens by the International Agency for Research on Cancer (IARC) were selected. Results: Among 21 chemicals, we obtained prediction results for 5 carcinogens, 8 non-carcinogens and 8 unpredictability chemicals. On the other hand, the carcinogenic potential of 5 carcinogens was found to be low by relevant research testing data and Oncologic TM tool. Seven of the 25 carcinogens (IARC Group 1) were wrongly predicted as non-carcinogens (false negative rate: 36.8%). We confirmed that the prediction error could be improved by combining genetic toxicity information such as mutagenicity. Conclusions: Some compounds, including inorganic chemicals and polymers, were still limited for applying toxicity prediction program. Carcinogenicity prediction may be further improved by conducting cross-validation of various toxicity prediction programs, or application of the theoretical molecular descriptors.

Detection of Hepatitis C Virus by RIA, Recombinant Immunoblot Assay and Nested RT-PCR (RIA, Recombinant Immunoblot Assay 및 Nested RT-PCR에 의한 C형 간염바이러스 검출)

  • Kim, Jae-Soo;Kim, Jong-Wan;Lee, Yun-Tai
    • The Journal of Korean Society of Virology
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    • v.30 no.2
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    • pp.151-159
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    • 2000
  • Hepatitis C virus (HCV) is one of the important human pathogen that can cause acute and chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Recently, the third generation radiation immuno assay (RIA) method has been developed as a very sensitive test to detect anti-HCV antibody. However, false positive is the problem with RIA test. To solve this the RIA results were compared to those of 5-antigen recombinant immunoblot assay (5-RIBA) and reverse transcription-polymerase chain reaction (RT-PCR). Among 12,767 serum samples tested from clinic visitors, total 275 (2.2%) samples were antibody positive by RIA. RIBA was performed with 148 RIA positives cases but among them was shown eighty five was antibody positive and sixty three (42.6%) was negative result. However, nested RT-PCR test was shown also carried out with 43 positive, 6 intermediates and 25 negatives of RIBA. As a result of the nested RT-PCR results, HCV antigen were detected in RIBA positive, 33.3% (2/6) RIBA intermediate and 12% (3/25). Clinical syndrome of all 148 patients as a with chronic active hepatitis (46.0%), cirrhosis (18.9%), hepatocellular carcinoma (8.1%) and others (27.0%) and they were positive in reaction by RIA test. But RIBA positive patients with 34.9% of chronic active hepatitis, 18.6% of cirrhosis, 4.6% of hepatocellular carcinoma and 41.9% of others were detected to be positive case by nested RT-PCR.

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